The present invention relates to a laminated tape adapted for imprinting of selected indicia or patterns thereon and a method and apparatus for imprinting the laminated tape.
In the prior art, a number of different techniques have been described for imprinting or applying different indicia or designs upon a selected surface, commonly in the form of an elongated tape. Such techniques and devices are possibly best known at present under the DYMO trademark for imprinting letters, numbers and similar indicia upon elongated tape formed from a pigmented plastic. These techniques and devices have commonly been employed for producing labels upon selected lengths of tape, the tape having an adhesive backing for attachment to the surface to which the label is to be applied.
Within the specific prior art referred to above, the various indicia are applied to the tape by creasing or producing stress within the tape in a pattern of narrow linear elements. Stressing the tape in this manner causes the linear features of the pattern to assume a white or lightened color relative to the normal tape color. Thus, this technique and apparatus have commonly been employed for producing labels and the like by applying numbers, letters and the like in selected order to the tape.
This technique has gained wide popularity, particularly in the production of labels as described above. However, the prior art technique has certain limiting characteristics. Because of the need for applying substantial pressure in order to produce the stress which results in a color change of the tape, its use is generally limited to application of designs such as letters, numbers or the like which are entirely formed by generally thin linear elements. The need to produce substantial stress within the tape for producing the color change makes it difficult to produce designs having any portions of substantial width or dimension. At the same time, tape adapted for use with the technique described above is generally limited to a pigmented plastic which is lightened or changed to a white color by the application of stress. Thus, this technique is generally limited to production of a tape having a single background color with the imprinted designs in the forms of letters, numbers or the like being either white or a lighter variation of the same background color.
A number of other techniques have also been made available in the prior art for imprinting laminated tape or the like. For example, Cutler et al U.S. Pat. No. 3,575,755 issued Apr. 20, 1971 relates to a laminated tape which includes a layer of heat-shrinkable material, a selected design being applied to the tape by applying heat which causes the heat-shrinkable material to be pulled away from selected areas in order to expose a separate layer of an underlying material having a contrasting color or the like and thereby forming a selected design or indicia. However, within this technique, its laminated tape is relatively complex at least in part because of the characteristics of the heat shrinkable material. In addition, the final design depends upon the amount of shrinkage for different parts of the design so that resolution of the finished design may tend to vary depending upon the tape and application of the selected design.
Kanzelberger U.S. Pat. No. 4,047,996 issued Sept. 13, 1977 relates to yet another method and apparatus for imprinting plastic plates wherein pigment is transferred from a carrying film in a technique commonly referred to as a hot stamp process. Thus, the method and apparatus of this reference is more commonly classified as an applique technique which differs substantially from the present invention in a manner to be described in greater detail below.
Perrington et al U.S. Pat. No. 4,123,309 issued Oct. 31, 1978 relates to a transfer letter system wherein pigment is transferred from a carrier film by selectively softening portions of a design with radiation and allowing those portions to adhere to another strip or tape of contrasting color. Here again, it may be seen that the technique of this reference also falls within the classification of an applique.
Finally, Scher et al U.S. Pat. No. 4,092,198 issued May 30, 1978 relates to a process for embossing and laminating wherein substantial pressures and temperatures are applied over long periods of time to a thermosetting plastic in order to produce a contrasting pattern having gradual color transitions. The process is relatively complex involving application of excessive pressures in the range of 800-1200 psi, for example, and excessive temperatures in the range of 260.degree.-310.degree. F. These conditions are necessary since the invention further contemplates formation of the design in a coating formed from a thermosetting plastic such as a melamine resin, the excessive pressures and temperatures being necessary to produce limited lateral movement resulting in a pattern formed by generally gradual color transitions.
Other techniques have also been available in the prior art. However, it is believed that those described above are generally representative of the prior art while indicating the need for a laminated tape and a method and apparatus of applying indicia thereto by simplified techniques permitting greater versatility in both the design applied to the tape and color combinations possible in the finished tape as well as simplicity of the tape and the method and apparatus for imprinting the tape.